The invention relates to a chip module and a method for producing such a chip module.
Smart cards are used in a multiplicity of applications. A smart card usually comprises a card body and a chip module inserted into the card body. The chip module is typically produced by mounting a chip having an integrated circuit onto a substrate with conductor structures. In the case of a smart card having a contact-based interface, the conductor structures comprise contact areas that can be contact-connected by a reader. In the case of a smart card having a contactless interface, contact regions for connecting an antenna are usually provided. The integrated circuit is supplied with power and data are transmitted by means of an electromagnetic field.
In the case of applications with very thin cards or electronic documents, so-called ultrathin modules are used, the total thickness of which is typically in the region of 200 μm or less. However, robustness and flexural strength are required for such applications.
Approaches to that effect achieve the robustness by using a chip that is relatively thick. Such a chip has a height in the region of 150 μm, for example. When using a protective encapsulation applied to the chip, and a leadframe as substrate, the thickness of which is typically in the region of 80 μm, the above mentioned module height is exceeded, however, with this arrangement.
In another arrangement, a chip having such a height is mounted using flip-chip technology. Furthermore, an encapsulation is dispensed with, such that the module thickness is dominated by the chip thickness. On account of the lack of encapsulation, this arrangement is susceptible to mechanical loads, which adversely affects the quality of the corresponding smart cards since failures can occur during mounting and in operation.
In a further arrangement, the chip is mounted on a steel plate having a thickness of approximately 120 μm. In this arrangement, the contact-connection of the antenna is effected directly on the chip, which is accompanied by an increased risk of chip damage during mounting and in operation.